GMAT Question of the Day - Daily to your Mailbox; hard ones only

It is currently 17 Oct 2019, 10:59

Close

GMAT Club Daily Prep

Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.

Customized
for You

we will pick new questions that match your level based on your Timer History

Track
Your Progress

every week, we’ll send you an estimated GMAT score based on your performance

Practice
Pays

we will pick new questions that match your level based on your Timer History

Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.

Close

Request Expert Reply

Confirm Cancel

The cost C, in dollars of producing x units of a certain commodity is

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:

Hide Tags

Find Similar Topics 
Intern
Intern
avatar
B
Joined: 30 Aug 2015
Posts: 24
GMAT 1: 570 Q47 V23
GMAT 2: 570 Q42 V27
GMAT 3: 680 Q50 V35
The cost C, in dollars of producing x units of a certain commodity is  [#permalink]

Show Tags

New post Updated on: 24 Apr 2016, 11:36
2
1
34
00:00
A
B
C
D
E

Difficulty:

  85% (hard)

Question Stats:

52% (02:09) correct 48% (02:00) wrong based on 318 sessions

HideShow timer Statistics

The cost C, in dollars of producing x units of a certain commodity is given by the formula C(x) = 10.000 + bx + ax^2 where a, and b are constants. What is the value of a?

(1) The cost of producing 500 units is $15.833.

(2) The cost of producing 1,000 units is twice the cost of producing 500 units.

Originally posted by inakihernandez on 24 Apr 2016, 10:20.
Last edited by Vyshak on 24 Apr 2016, 11:36, edited 1 time in total.
Edited the url
Most Helpful Expert Reply
Math Expert
avatar
V
Joined: 02 Aug 2009
Posts: 7971
The cost C, in dollars of producing x units of a certain commodity is  [#permalink]

Show Tags

New post 24 Apr 2016, 10:58
12
7
inakihernandez wrote:
The cost C, in dollars of producing x units of a certain commodity is given by the formula C(x) = 10.000 + bx + ax^2 where a, and b are constants. What is the value of a?

(1) The cost of producing 500 units is $15.833.

(2) The cost of producing 1,000 units is twice the cost of producing 500 units.


Hi
the equation has got two constants a and b..

lets see the statements



(1) The cost of producing 500 units is $15.833.
we have two constants a and b, and one equation
Insuff

(2) The cost of producing 1,000 units is twice the cost of producing 500 units
here when you make two quation and equate them you will realize you can find answer..
\(C(1000) = 10.000 + b*1000 + a1000^2\) ..
\(C(500) = 10.000 + b*500 + a500^2\) ..

now \(C(1000) = 2* C(500)\)..
so \(10.000 + b*1000 + a1000^2 = 2( 10.000 + b*500 + a500^2 )\)..
\(10.000 + b*1000 + a1000^2 = 20.000 + b*1000 + 2*a*500^2\)
b will get cancelled and you can find value of a..
Suff

Hope it helps
_________________
General Discussion
EMPOWERgmat Instructor
User avatar
V
Status: GMAT Assassin/Co-Founder
Affiliations: EMPOWERgmat
Joined: 19 Dec 2014
Posts: 15263
Location: United States (CA)
GMAT 1: 800 Q51 V49
GRE 1: Q170 V170
Re: The cost C, in dollars of producing x units of a certain commodity is  [#permalink]

Show Tags

New post 24 Apr 2016, 10:47
2
Hi inakihernandez,

You should post this question in the DS sub-Forum here:

gmat-data-sufficiency-ds-141/

GMAT assassins aren't born, they're made,
Rich
_________________
Contact Rich at: Rich.C@empowergmat.com
Image


The Course Used By GMAT Club Moderators To Earn 750+

souvik101990 Score: 760 Q50 V42 ★★★★★
ENGRTOMBA2018 Score: 750 Q49 V44 ★★★★★
Marshall & McDonough Moderator
User avatar
D
Joined: 13 Apr 2015
Posts: 1685
Location: India
GMAT ToolKit User
Re: The cost C, in dollars of producing x units of a certain commodity is  [#permalink]

Show Tags

New post 24 Apr 2016, 11:02
2
2
C(x) = 10.000 + bx + ax^2
a = ?

St1: C(500) = 10 + 500b + a(25*10^4 ) = 15.833
We have 2 unknowns and hence value of 'a' cannot be determined without knowing the value of 'b'
Not Sufficient

St2: C(1000) = 2*C(500)
10 + 1000b + a(10^6) = 20 + 1000b + a(50*10^4)
a(10^6 - 5*10^5) = 10
Sufficient to determine the value of 'a'

Answer: B
Senior Manager
Senior Manager
User avatar
Joined: 11 Nov 2014
Posts: 315
Location: India
Concentration: Finance, International Business
WE: Project Management (Telecommunications)
GMAT ToolKit User
Re: The cost C, in dollars of producing x units of a certain commodity is  [#permalink]

Show Tags

New post 24 Apr 2016, 11:10
1
Vyshak wrote:
C(x) = 10.000 + bx + ax^2
a = ?

St1: C(500) = 10 + 500b + a(25*10^4 ) = 15.833
We have 2 unknowns and hence value of 'a' cannot be determined without knowing the value of 'b'
Not Sufficient

St2: C(1000) = 2*C(500)
10 + 1000b + a(10^6) = 20 + 1000b + a(50*10^4)
a(10^6 - 5*10^5) = 10
Sufficient to determine the value of 'a'

Answer: B


how did you get this?
a(25*10^4 )
a(50*10^4)
Marshall & McDonough Moderator
User avatar
D
Joined: 13 Apr 2015
Posts: 1685
Location: India
GMAT ToolKit User
Re: The cost C, in dollars of producing x units of a certain commodity is  [#permalink]

Show Tags

New post 24 Apr 2016, 11:13
1
paidlukkha wrote:
Vyshak wrote:
C(x) = 10.000 + bx + ax^2
a = ?

St1: C(500) = 10 + 500b + a(25*10^4 ) = 15.833
We have 2 unknowns and hence value of 'a' cannot be determined without knowing the value of 'b'
Not Sufficient

St2: C(1000) = 2*C(500)
10 + 1000b + a(10^6) = 20 + 1000b + a(50*10^4)
a(10^6 - 5*10^5) = 10
Sufficient to determine the value of 'a'

Answer: B


how did you get this?
a(25*10^4 )
a(50*10^4)


Hi,

I have skipped some multiplication steps in my explanation.

x = 5*10^2 --> x^2 = 25*10^4

2*C(500) --> 2(10 + 500b + 25*10^4) --> 20 + 1000b + 2*25*10^4
Veritas Prep GMAT Instructor
User avatar
V
Joined: 16 Oct 2010
Posts: 9705
Location: Pune, India
Re: The cost C, in dollars of producing x units of a certain commodity is  [#permalink]

Show Tags

New post 24 Apr 2016, 21:04
8
inakihernandez wrote:
The cost C, in dollars of producing x units of a certain commodity is given by the formula C(x) = 10.000 + bx + ax^2 where a, and b are constants. What is the value of a?

(1) The cost of producing 500 units is $15.833.

(2) The cost of producing 1,000 units is twice the cost of producing 500 units.


Let me point out here that this is a (C) trap question. The first statement will give an equation in a and b. So we know that we cannot find the value of a. When we look at the second statement, we see another equation in a and b which is not a multiple of the first equation and suddenly, it seems that we will be able to solve both equations simultaneously and get the answer. So (C) seems to be correct. But that is just too easy. Beware of the (C) trap. This should make you think - can I solve the question using a single statement alone. Make the equation of statement 2 since it gives you some convoluted relative data. When you do, you see that b gets canceled and in fact, you can get the value of a. Note that you cannot find the value of b from the second statement alone but the question doesn't ask for the value of b. We only need the value of a and hence second statement is sufficient alone.
_________________
Karishma
Veritas Prep GMAT Instructor

Learn more about how Veritas Prep can help you achieve a great GMAT score by checking out their GMAT Prep Options >
Current Student
User avatar
G
Joined: 28 Nov 2014
Posts: 818
Concentration: Strategy
Schools: Fisher '19 (M$)
GPA: 3.71
Reviews Badge
Re: The cost C, in dollars of producing x units of a certain commodity is  [#permalink]

Show Tags

New post 09 Oct 2016, 04:29
The correct statement 1 is
(1) The cost of producing 500 units of this commodity is $15833

It is NOT 15.833 although that won't affect the OA.
SVP
SVP
User avatar
P
Joined: 03 Jun 2019
Posts: 1699
Location: India
Premium Member Reviews Badge CAT Tests
Re: The cost C, in dollars of producing x units of a certain commodity is  [#permalink]

Show Tags

New post 20 Sep 2019, 22:51
inakihernandez wrote:
The cost C, in dollars of producing x units of a certain commodity is given by the formula C(x) = 10.000 + bx + ax^2 where a, and b are constants. What is the value of a?

(1) The cost of producing 500 units is $15.833.

(2) The cost of producing 1,000 units is twice the cost of producing 500 units.


Given: The cost C, in dollars of producing x units of a certain commodity is given by the formula C(x) = 10.000 + bx + ax^2 where a, and b are constants.

Asked: What is the value of a?

(1) The cost of producing 500 units is $15.833.
C(x) = 10.000 + bx + ax^2
x = 500
C(x) = $15.833 = 10 + 500b + 250000a
Since there are 2 unknowns
NOT SUFFICIENT

(2) The cost of producing 1,000 units is twice the cost of producing 500 units.
10 + 1000b + 1000000a = 2(10 + 500b + 250000a)
1000000a = 10 + 500000a
500000a = 10
\(a = \frac{1}{50000}\)
SUFFICIENT

IMO B
_________________
"Success is not final; failure is not fatal: It is the courage to continue that counts."

Please provide kudos if you like my post. Kudos encourage active discussions.

My GMAT Resources: -

Efficient Learning
All you need to know about GMAT quant

Tele: +91-11-40396815
Mobile : +91-9910661622
E-mail : kinshook.chaturvedi@gmail.com
SVP
SVP
User avatar
P
Joined: 03 Jun 2019
Posts: 1699
Location: India
Premium Member Reviews Badge CAT Tests
Re: The cost C, in dollars of producing x units of a certain commodity is  [#permalink]

Show Tags

New post 08 Oct 2019, 10:34
inakihernandez wrote:
The cost C, in dollars of producing x units of a certain commodity is given by the formula C(x) = 10.000 + bx + ax^2 where a, and b are constants. What is the value of a?

(1) The cost of producing 500 units is $15.833.

(2) The cost of producing 1,000 units is twice the cost of producing 500 units.


Given: The cost C, in dollars of producing x units of a certain commodity is given by the formula C(x) = 10.000 + bx + ax^2 where a, and b are constants.

Asked: What is the value of a?

(1) The cost of producing 500 units is $15.833.
15.833 = 10 + 500b + 25000a
Since b is unknown, a can not be found out
NOT SUFFICIENT

(2) The cost of producing 1,000 units is twice the cost of producing 500 units.
10 + 1000b + 1000000a = 2 (10 + 500b + 250000a)
10 + 1000b + 1000000a = 20 + 1000b + 500000a
10 = 500000a
a = 10/500000
SUFFICIENT

IMO B
_________________
"Success is not final; failure is not fatal: It is the courage to continue that counts."

Please provide kudos if you like my post. Kudos encourage active discussions.

My GMAT Resources: -

Efficient Learning
All you need to know about GMAT quant

Tele: +91-11-40396815
Mobile : +91-9910661622
E-mail : kinshook.chaturvedi@gmail.com
GMAT Club Bot
Re: The cost C, in dollars of producing x units of a certain commodity is   [#permalink] 08 Oct 2019, 10:34
Display posts from previous: Sort by

The cost C, in dollars of producing x units of a certain commodity is

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  





Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne